It usually starts with a sentence a family says to each other before they ever say it to a doctor: “He hasn’t been himself since the summer.” The walking got heavier. The words come slower. There is a new vagueness about the afternoons, a reluctance to go out, a nap that was never there before. Nobody can point to a day it began, because there wasn’t one.
And somewhere back in June, there was a bump. A doorframe in a dark hallway, a slip on the back step, a knock getting into the car. He said he was grand. He was grand, for about six weeks. Then the brain he bumped began to tell on him, and by the time anyone was worried enough to ring the surgery, the bump had been forgotten by everyone, including him.
This is chronic subdural haematoma, and it is one of the few conditions in later life that genuinely looks like dementia, behaves like decline, and is very often fixed in a single operation.
TL;DR
- A chronic subdural haematoma is a slow bleed over the surface of the brain that typically declares itself weeks after a minor head knock, not hours. Its symptoms are gradual: unsteadiness, confusion, slowed thinking, headache, a change in personality.
- Risk climbs steeply with age. Published incidence for operated cases runs at 1.77 per 100,000 per year in people in their 50s and 25.71 in their 80s, roughly a fifteen-fold difference. Ireland’s population aged 85 and over has grown by about half in a decade, three times faster than the population overall.
- Irish public guidance barely mentions it. The word “subdural” appears nowhere in the 478 condition pages of the HSE Health A to Z, and the HSE’s head injury page tells readers to expect recovery “within 2 weeks”, naming warfarin as the only blood thinner.
- The test is a CT brain, and your GP can order it directly. CT Brain is on the HSE GP Access to Community Diagnostics list, free, for the full adult population, with no medical card required.
- Treatment changed in late 2024. Three randomised trials of middle meningeal artery embolisation reported within days of each other, two positive and one not. Separately, the Dex-CSDH trial showed that steroids make outcomes worse, not better.
What is actually happening in there
The brain shrinks a little with age. That is normal, and it is not the same as dementia. But it means the brain sits with slightly more space around it inside the skull, and the small bridging veins that run from the brain’s surface to the membranes lining the skull are stretched a bit tighter than they were at forty.
A knock that a younger head would shrug off can tear one of those stretched veins. The bleeding is slow and low-pressure, so there is no sudden collapse, no dramatic headache, nothing that announces itself. A thin film of blood collects between the brain and its covering, and then, over several weeks, it does something unhelpful: it draws in fluid, grows a fragile new membrane with leaky vessels of its own, and keeps enlarging. By week five or six it is big enough to press on the brain underneath.
That slow timeline is the entire problem. The interval between the injury and the first symptom is often four to twelve weeks, which is long enough that nobody connects the two. In a substantial minority of cases there is no remembered injury at all, because the knock was too trivial to file away.
Why it gets called something else first
Writing in Age and Ageing in March 2025, a team from the UK’s highest-volume treatment centre described the typical presentation as “an insidious onset of broad-ranging symptoms including impaired cognition, gait, balance and mobility, often with headache”. Read that list again and notice what it resembles.
Unsteadiness goes to the falls clinic. Slowed thinking and word-finding trouble go to the memory service. Low mood and withdrawal get a conversation about depression. A one-sided weakness gets a stroke workup. Each of those is a reasonable response to the symptom in front of you, and each of them is a different queue in a different building. The thing that joins them up is a single scan that nobody has thought to order, because the referral was never framed as a head injury in the first place.
If you have read our pieces on normal pressure hydrocephalus or delirium, this will feel familiar. The pattern repeats: a treatable cause of decline gets absorbed into a story about ageing, and the story is harder to dislodge than the condition.
Who this happens to, and how often
A Cambridge study published in Acta Neurochirurgica in 2021 worked out the incidence of operated chronic subdural haematoma by age band, per 100,000 people per year:
- 50 to 59: 1.77
- 60 to 69: 4.32
- 70 to 79: 15.08
- 80 to 89: 25.71
- 90 and over: 15.49
The rate in the eighties is roughly fifteen times the rate in the fifties. The same authors projected a 53% rise in operations across their region by 2040 from demographic change alone, with no change in underlying risk. The Age and Ageing authors go further, describing chronic subdural haematoma as “projected to become the most common cranial neurosurgical pathology by 2030”.
Ireland is squarely in the path of that. Central Statistics Office estimates put the population aged 65 and over at 891,000 in April 2026, up from 629,900 in 2016. The 85 and over group, where the risk concentrates most, went from 67,300 to 100,900 across the same decade. That is close to a 50% increase, against 17% for the population as a whole: the group most likely to develop this condition is growing three times faster than the country.
Two other things raise risk. One is anything that thins the blood, including warfarin, the newer anticoagulants such as apixaban, rivaroxaban, edoxaban and dabigatran, and antiplatelets such as aspirin and clopidogrel. The other is alcohol, which both increases falls and affects clotting. None of this is an argument for stopping a medicine that is preventing strokes. It is an argument for taking a head knock seriously when you are on one.
What Irish guidance actually says, and does not say
Here is the part that should change how you approach your GP.
The HSE Health A to Z is the public’s front door to medical information in Ireland. It carries 478 condition pages. Not one of them contains the word “subdural” or the word “haematoma”. The closest entry is “Head injury and concussion”, a short page that opens by telling readers that most head injuries are not serious and that you “should make a full recovery within 2 weeks”. The longest horizon it offers is concussion symptoms that “sometimes may not appear for up to 3 weeks”. It names warfarin as a reason to be more careful, and no other blood thinner: no apixaban, no rivaroxaban, no clopidogrel. The word “older” does not appear on it at all.
So the national guidance gives a reader a two to three week window and a single drug name, for a condition that usually turns up at six weeks in someone who is very likely taking a drug that is not listed.
There is also a national protocol. The HSE Trauma System Implementation Programme published its “Protocol for the management of acute traumatic brain injury in non-neurosurgical hospitals” on 18 October 2024. It is a genuinely useful document, and subdural haematoma does appear in it, in the appendix table of referral criteria for the National Neurosurgical Centre at Beaumont Hospital, where a subdural more than 5mm thick in a patient with a Glasgow Coma Scale of 13 to 15 triggers a neurosurgical discussion.
But read the title again. It is a protocol for acute traumatic brain injury, for the person who arrives at an emergency department after an accident. The words “older”, “elderly” and “aged” do not appear in its body text, nor do “anticoagulant”, “frailty” or “geriatric”. That is not a criticism of the document, which is doing the job it was scoped to do. It is an observation that the person who walks into a GP surgery eight weeks after a forgotten bump, fully conscious, with a family saying he has not been himself, is not inside any of it.
One detail in that appendix deserves to be reported accurately rather than alarmingly, because it is easy to misread. Among the exceptions requiring case by case discussion, the table lists “Age > 75 years”, noting that the prognosis in that age group with severe traumatic brain injury, meaning a Glasgow Coma Scale of 3 to 8, is extremely poor. That applies to patients who are comatose after major trauma. It has nothing to do with the alert 78 year old with a chronic subdural, who is routinely and successfully operated on. If anyone ever tells you otherwise, that is the distinction to ask about.
The scan is easier to get than most people think
This is the most useful thing in this article, so it gets its own heading.
Under the HSE’s GP Access to Community Diagnostics scheme, GPs can refer directly for X-ray, CT, MRI and DXA through contracted private providers, and CT Brain is explicitly on the CT list. Crucially, that scheme is open to the full adult population of Ireland from age 16. You do not need a medical card. (Community ultrasound is the one that does require a medical card, GP visit card or Health Amendment Act card, which is a distinction worth knowing if you have read our piece on the Health (Amendment) Act card.)
The referral form asks the GP to mark the request urgent or routine. So the conversation to have is not “can we get a scan”, which sounds like a big ask. It is: “He had a knock to the head in the summer and he has gone downhill since. Can we get a CT brain to rule out a subdural?” That is a specific, answerable question, and it names the thing you want excluded.
If symptoms are moving quickly, or there is new weakness, drowsiness, vomiting or a seizure, that is not a community scan. That is an emergency department, today.
What treatment looks like now
The standard operation is burr hole drainage: one or two small holes in the skull, the old blood washed out, a drain left in for a day or so. It is done under general or local anaesthetic, and people are often noticeably better within days.
The largest real-world study of how this goes was run across 26 neurosurgical units in the UK and Ireland by the British Neurosurgical Trainee Research Collaborative, covering 1,205 patients. Burr hole surgery was used in 89% of cases. Mortality in the neurosurgical unit was 2%, and 9% needed a repeat operation within 60 days for a symptomatic recurrence. Two findings from it are worth carrying into a conversation with a surgical team: leaving a drain in after washout independently reduced both recurrence and poor outcomes, and enforced bed rest afterwards made outcomes worse. Reassuringly, being on antiplatelet medication beforehand did not predict a worse functional outcome.
Recurrence is the long-standing weakness of burr hole surgery, and that is what late 2024 was about. Three randomised trials of middle meningeal artery embolisation, a procedure that threads a catheter up to the artery feeding those leaky new membranes and blocks it off, reported almost together. They did not all agree, and anyone telling you they did is overselling it.
- EMBOLISE randomised 400 patients due for surgery. Repeat surgery within 90 days fell from 11.3% to 4.1% when embolisation was added. Serious procedure-related events occurred in 2.0%, including disabling stroke in two patients.
- STEM randomised 310 patients, mean age 73. Its combined failure measure at 180 days fell from 36% to 16%, with no increase in disabling stroke or death at 30 days.
- MAGIC-MT, the largest at 722 patients, found no significant difference in recurrence or progression: 6.7% against 9.9%, which did not reach statistical significance. It did find fewer serious adverse events in the embolisation group, 6.7% against 11.6%.
The fair summary is that embolisation reduces the chance of needing a second operation, that the size of that benefit is still being argued over, and that it looks reasonably safe. It is of particular interest for people in whom stopping an anticoagulant for surgery is itself dangerous, since the procedure does not require the same interruption.
One thing the evidence is unambiguous about is what not to do. The Dex-CSDH trial randomised 748 patients, mean age 74, to a two-week course of dexamethasone or placebo. Fewer people had a good outcome at six months on the steroid, 83.9% against 90.3%, and there were more adverse events. It reduced repeat operations, but at a cost to how people actually ended up. Steroids are not the answer here.
Driving, and the rule people get wrong
Ireland’s Sláinte agus Tiomáint medical fitness to drive guidelines treat chronic and acute subdural haematoma very differently, and families frequently assume the harsher rule applies.
For a chronic subdural haematoma treated surgically, an ordinary Group 1 licence holder (car, motorcycle, tractor) is permitted to drive on recovery, provided there is no significant residual disability. For a spontaneous acute subdural treated by craniotomy, it is six months off the road. Group 2 licence holders, meaning buses and trucks, face six months to a year and an individual consultant assessment.
In every one of those scenarios the driver should notify the National Driver Licence Service. Guidelines are revised, so check the current edition on rsa.ie rather than relying on a figure from an article, including this one.
What to do with all this
If you are supporting someone whose walking, thinking or mood has changed over a few weeks rather than a few years, do three things.
Work out the timeline, and write it down. When did it start? What was different the month before? Ask explicitly about falls and knocks, including ones that seemed too small to mention, and ask other people in the house, because the person affected often genuinely does not remember.
Bring the medicines list. Not a summary: the actual list, including anything bought over the counter. Whether someone is on an anticoagulant or antiplatelet changes how urgently this is taken.
Name the thing you want ruled out. “Could this be a subdural?” is a short sentence that redirects an appointment.
Most of the people this happens to get better. That is the frustrating and hopeful part of it in equal measure: the gap between a treatable brain condition and a slow decline nobody questions is often just one scan and one person willing to ask for it.
At Críonna Health we write about the parts of ageing that get mistaken for ageing itself. If something has changed in weeks rather than years, that is worth a question, not a shrug.
This article is for general information and is not a substitute for individual medical advice. If you are worried about someone’s symptoms, contact your GP, and in an emergency ring 112 or 999.
📷 Photo by Jakub Żerdzicki on Unsplash
